Commodore 64 peripherals

Many European software developers wrote their own fast tape-loaders which replaced the internal KERNAL code in the C64 and offered loading times more comparable to disk drive speeds.

Due to lack of hardware support for detecting track zero position, Commodore DOS formatting routines and many complex software copy-protection schemes (which used data stored on nonstandard tracks on floppies) had to rely on moving the head specified number of steps in order to make sure that the desired head position for formatting or reading the data was reached.

Also, as with the C64, 1541 drives tended to overheat due to a design that did not permit adequate cooling (potentially fixed by mounting a small fan to the case).

Not long after the 1541's introduction, third-party developers demonstrated that performance could be improved with software that took over control of the serial bus signal lines and implemented a better transfer protocol between the computer and disk.

In 1984 Epyx released its FastLoad cartridge for the C64, which replaced some of the 1541's slow routines with its own custom code, thus allowing users to load programs in a fraction of the time.

As a free alternative to FastLoad cartridges, numerous pure software turbo-loader programs were also created that were loaded to RAM each time after the computer was reset.

The best of these turbo-loaders were able to accelerate the time required for loading a program from the floppy drive by a factor of 20x, demonstrating the default bus implementation's inadequacy.

As an alternative to the feeble performing 1541 or the relatively expensive IEEE bus adapter and associated peripherals, a number of third-party serial-bus drives such as the MSD Super Disk and Indus GT appeared that often offered better reliability, higher performance, quieter operation, or simply a lower price than the 1541, although often at the expense of software compatibility due to the difficulty of reverse engineering the DOS built into the 1541's hardware (Commodore's IEEE-based drives faced the same issue due to the dependence of the DOS on features of the Commodore serial bus).

It was also possible, without requiring a VIC-switch, to connect two Commodore 64s to one 1541 floppy disk drive to simulate an elementary network, allowing the two computers to share data on a single disk (if the two computers made simultaneous requests, the 1541 handled one while returning an error to the other, which surprised many people who expected the 1541's less-than-stellar drive controller to crash or hang).

However, enthusiasts could use this drive to transfer data between typical PC MS-DOS and the Commodore with special software, such as SOGWAP's Big Blue Reader.

The Lt. Kernal mated a 10 megabyte Seagate ST-412 hard drive to an OMTI SASI intelligent controller, creating a high speed bus interface to the C64's expansion port.

The Lt. Kernal shipped with a disk operation system (DOS) that, among other things, allowed execution of a program by simply typing its name and pressing the Return key.

The DOS also included a keyed random access feature that made it possible for a skilled programmer to implement ISAM style databases.

[9] An optional multiplexer allowed one Lt. Kernal drive to be shared by as many as sixteen C64s or C128s (in any combination), using a round-robin scheduling algorithm that took advantage of the SCSI bus protocol's ability to handle multiple initiators and targets.

The 1520 was based upon the Alps Electric DPG1302, a mechanism which also formed the basis of numerous other inexpensive plotters for home computers of the time (e.g. the Atari 1020).

Interfaces for all popular home computers at the time were made, including Apple II, Commodore 64, and Acorn, and later for Schneider, Atari ST, and IBM PC.

[29][30] In 1987 there was a cartridge port device to measure EEG directly for use in exercise programs, called "BodyLink" produced by the company Bodylog in New York City, USA.

[31] Schippers-Medizintechnik in Germany produced a user port attached EMG device to allow a physician to analyze such things as stress level, and assisting in finding a better position for work.

In Germany the very restrictive rules of the state-owned telephone system prevented widespread use of inexpensive, non-telco licensed modems, prompting the use of inferior acoustic couplers instead.

Possibly the most complex C64 peripheral was the Mimic Systems Spartan, which added an entire new computer architecture to the C64, with its own 6502 CPU and expansion bus, for software and hardware compatibility with the Apple II.

The long delay between announcement and availability, along with heavy promotion including full-page ads running monthly in the Commodore press, made the Spartan an infamous example of vaporware.

As GEOS made heavy use of a primitive, software-controlled form of swap space, it tended to be slow when used exclusively with floppy disks or hard drives.

Due to the lack of available 17xx-series Commodore REUs, and then their later discontinuation, Berkeley Softworks, the publishers of GEOS, developed their own 512 kB RAM expansion cartridge - the GeoRAM.

Freezer cartridges had the capability to not only manually reset the machine, but also to dump the contents of the computer's memory and send the output to disk or tape.

The Lt. Kernal hard drive subsystem included a push button on the host adapter called ICQUB (pronounced "ice cube"), which could be used to halt a running program and capture a RAM image to disk.

As the Commodore 64 featured a digitally controlled semi-analogue synthesizer as its sound processor, it was not surprising to discover an abundance of software and hardware designed to expand upon its capabilities.

[21] Recently a few professional musicians have used the Commodore 64's unique sound to provide some or all of the synthesizer parts required for their performances or recordings; an example being the band Instant Remedy.

The most well-known accelerator for the C64 is probably Creative Micro Designs' SuperCPU, which was equipped with the WDC W65C816S (the static core version of the 65C816) clocked at 20 MHz, and with up to 16 MB of RAM if combined with CMD's SuperRamCard.

The difference to other SD-based and .d64 mounting cartridges like the MMC64, Super Snapshot 2007 or MMC Replay is, that the 6502 that powers the 1541 Floppy and the 1541's mechanical behavior (even sound) is fully emulated, making it theoretically compatible with almost anything.

Additional features include BASIC extension, DOS Wedge, file manager, machine code monitor, fast loader, BIOS setup screen.